Hikaru is a very short girl with light red braided hair and fiery red eyes that reflect her passionate and determined nature. Despite her small stature, she exudes a strong presence filled with energy and courage.

She is seen wearing three distinct outfits throughout the series. Her school uniform consists of a red long-sleeved blouse with a collar and a white ribbon, paired with a black skirt lined with red at the bottom and a white petticoat. After being summoned to Cephiro, she dons white armor adorned with rubies. When her armor reaches its final form, she wears a short red, white, and gold armor-like dress, completed with a flowing red cape and a matching tiara-like headpiece.

Hikaru Shidou, Umi Ryuuzaki, and Fuu Hououji are strangers brought together by fate when they meet during a seemingly normal field trip to Tokyo Tower.

Hikaru Shidou is a pure hearted, honest, and straightforward girl whose cheerful spirit often shines brighter than her small stature. Though she is quite short and frequently mistaken for an elementary student rather than the junior high school girl she truly is, Hikaru’s boundless energy and athleticism allow her to excel physically, especially in jumping. Trained in kendo from a young age, she wields a sword with impressive skill. Her first weapon was a simple sword, later replaced by one forged from Escudo, a special blade that bursts into flames when touched by anyone other than herself. Despite her innocent and simple nature, Hikaru stands out as the bravest, strongest, and most mature among the Magic Knights.

The youngest in her family, Hikaru grew up in a household that ran a kendo dojo, where she learned discipline and resilience. She has three older brothers, Satoru, Masaru, and Kakeru, who dote on her endlessly, which explains her tomboyish personality and competitive nature. Little is mentioned about her parents, but in one manga omake, it is humorously revealed that her father left on a training journey after she defeated him in a kendo match at the age of five. This playful story highlights Hikaru’s natural talent and her spirited, determined attitude even as a child.

Among the three Magic Knights summoned by Princess Emeraude, Hikaru possesses the strongest heart. She is often the one who lifts the spirits of her companions, encouraging Umi Ryuuzaki and Fuu Hououji to stay hopeful even in the face of despair. Her determination and optimism make her the first to accept the duties of a Magic Knight without hesitation. Though she can be headstrong and a little childish, her sincerity and enthusiasm inspire those around her. In the anime adaptation, Hikaru’s emotional depth is further explored as she struggles deeply with guilt over Princess Emeraude’s death, showing her compassionate yet fragile side.